Rates of growth, ribosome synthesis and elongation factor synthesis in a tufA defective strain of E. coli.
A tufA defective strain of E. coli was isolated which by a single deletion event acquired a tufA-lacZ fusion gene and lost the normal functional tufA gene (see accompanying paper). A correlation between the growth rate of protein synthesis was decreased to about 50% in the tufA defective strain whereas the number of EF-Tu molecules per ribosome was about 80% compared to a normal strain. The results indicate that tufB gene expression was preferentially stimulated in the tufA defective strain but the increased EF-TuB synthesis was not sufficient to make up for the loss of normal EF-TuA synthesis. Introduction of a plasmid that carries a complete tufA gene and the preceeding fusA gene but not the str-promotor into the tufA defective strain did not alleviate the slow growth or low rate of EF-Tu synthesis showing that the high rate of EF-TuA synthesis compared to the other proteins in the str operon is not augmented by a strong second promotor for the tufA gene. The tufA-lacZ fusion which takes the place of the normal tufA gene was expressed at a high rate and the beta-galactosidase activity increased with the growth rate as expected.
D001426:Bacterial Proteins / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D009154:Mutation; D010445:Peptide Elongation Factors / Q000096:biosynthesis*; D010641:Phenotype; D012269:Ribosomal Proteins / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics*; D001616:beta-Galactosidase / Q000378:metabolism
D001426:Bacterial Proteins; D010445:Peptide Elongation Factors; D012269:Ribosomal Proteins; D014157:Transcription Factors; D001616:beta-Galactosidase